Manufacture of wrought iron



Oct. 19, 1937.

C. E. GROSS MANUFACTURE OF WROUGHT-IRON Filed Jx l ly :50, 1932 G U Q Patented Oct. 19, 1937 UNITED STATES rarer Fries MANUFACTURE OF VIEUUGHT IRON Application July 30, 1932, Serial No. 626,987

2 Claims.

This invention relates broadly to the manufacture of wrought iron, and more particularly to the manufacture of wrought iron in accordance with the now well known Aston process. The in- 5 vention further relates to certain improvements in the manufacture of wrought iron and which are particularly adaptable to the Aston process.

The invention still further relates to certain improved methods for the manufacture of wrought iron, which methods result in numerous advantages overthe manufacture of wrought iron by the Aston process as heretofore known.

The Aston process for the manufacture of wrought iron is now well known and, in a preferred manner of procedure, comprises pouring molten ferrous material into a slag bath so that the solidified or partly solidified granules of fer rous material formed during the pouring are in dividually coated with slag and Welded together to form at the bottom of the slag receptacle a compressible mass or ball of wrought iron. The

ball thus formed can be compressed to form a bloom which may then be rolled or reduced to a billet or any other desired form.

In order to insure the uniform distribution of the molten ferrous material throughout the slag, and to avoid excessive heating of any one portion of the latter, there have been devised certain methods of and apparatus for automatically pouring molten ferrous material into a slag bath in such a manner that the desired result is obtained. Such methods are specifically described and claimed in WillePatent No. 1,890,660, granted Dec. 13, 1932, and such apparatus is specifically described and claimed in Wille Patent No. 1,933,577, granted Nov. '7, 1933.

I have devised certain methods of procedure in the manufacture of wrought iron by the Aston process as described in said Wille patents delo signed to facilitate the operations, reduce the amount of time required for the completion thereof so that the process may be carried out more efficiently and more expeditiously, and otherwise increase the efficiency of the operation and k5 maintain the high standard of quality of the product. Other methods and apparatus described herein are described and claimed in the copendmg application of Herman A. Brassert, Serial No.

626,984, filed of even date herewith.

A plant for the manufacture of wrought iron is provided which comprises means for supplying molten ferrous material, means for supplying slag, a press, and one or more shotting maadapted for rotary movement. A tiltable ladle is preferably supported on the table and means are preferably provided for reciprocating the platform, rotating the table and tilting the ladle, all of said operations being preferably performed antomatically. The reciprocable platform is preferably supported by the beam of a platform scale so that the amount of ferrous material poured from each machine into a receptacle of slag positioned therebeneath may be accurately determined.

In the plant arrangement previously mentioned, a track is preferably provided to connect the shotting machine or machines and a slag transfer station, preferably adjacent a ball press, whereby cars carrying slag receptacles may be readily shifted from one point in the plant to another. The track may also, if desired, lead toa point adjacent the slag furnace or furnaces. Briefly, the arrangement in a present preferred embodiment is such that empty slag receptacles may be provided with slag, preferably at the slag transfer station. The cars are then moved toposition the slag receptacles beneath the shotting machines which pour the required amount of molten ferrous material into the slag and distribute it therethrough. In order to increase the speed of production a plurality of shotting machines are employed whereby several slag receptacles may simultaneously receive acharge of molten ferrous material into their respective slag contents. The cars are shifted from the shotting machines, excess slag is transferred from the slag receptacles and the balls are removed therefrom adjacent the press for treatment therein. Preferably the excess slag is decanted from each slag receptacle, and it is found highly advantageous to transfer the excess slag, either by decantation or otherwise, into another slag receptacle disposed at the same level, preferably directly, and this may conveniently be done by lifting and tilting the slag receptacle, and, after the desired quantity of excess slag has been removed, dump ing out the ball, "preferably directly into the press. This feature is described and claimed in the copending application ofJames Aston and Herman A. Brassert, Serial No. 626,985, filed of even date herewith. The excess slag is preferably reused for the formation of one or more additional balls, with or without additions. It is preferred to replenish the excess slag with additional molten slag. This feature is described and claimed in the copending application of James Aston and Edward B. Story, Serial No. 626,986, filed of even date herewith. I find it of especial advantage to effect the slag replenishment at the slag transfer station.

The means for supplying molten ferrous material may be of any suitable or well known type, and in the production of limited quantities of wrought iron it is found that certain advantages are obtained by using one or more cupolas wherein the metal is melted and one or more Bessemer converters to which the melted metal is transferred for refining. The converter or converters may be tapped into a transfer receptacle which delivers the refined metal to the shotting machines.

The invention may be fully understood by reference to the accompanying drawing taken in connection with the following description, the drawing illustrating a present preferred embodiment of the invention which is nowise to limit the scope thereof as it is intended merely as an example. Other details, objects and advantages of the invention will become apparent as the description proceeds.

The drawing is a schematic diagram of a plant layout which I have provided for the rapid and efficient production of. wrought iron by the Aston process.

Referring more particularly to the drawing, there are provided three cupolas, designated generally by reference numeral 2, erected within an enclosure 3 and which may be of standard or Well known construction. There are also provided two Bessemer converters which may be of standard or well known construction, such converters being designated generally by reference numeral 8. The usual converter accessories are provided.

A platform 9 is provided which extends longitudinally from thecupolas past the converters. A track I!) is provided on the platform, such track extending from a point beneath the metal runouts of the; cupolas past the converters. A transfer car provided with a tilting ladle operates on the track H3. The molten metal from the cupolas is tapped into the tilting ladle, the slag is raked off and the metal is otherwise treated as may be desired, and the car is then moved to a position opposite one or the other of the converters 8 and the molten metal is poured into such converter. The converter is then rotated to blowing position and the metal is Bessemerized or refined. V

The cupolas may be tapped alternately, the three cupolas furnishing approximately the right amount of metal to keep the converters in operation. The converters may be operated alternate ly or their operation may be staggered, one converter blowing while the other is being tapped and charged. If smaller capacity is desired one of the converters may be used alone and one or two of the cupolas shut down. In any event, the mechanism described produces batches of refined ferrous material at spaced intervals. The amount of material in each batch and the intervals between batches will be controlled so as to coordinate with the shotting apparatus presently to be referred to.

There are provided a pair of slag furnaces, designated generally by reference numeral l3, which are preferably of the tilting open hearth type and which are provided with run-outs l4. These furnaces may be of standard or well known construction. The slag furnaces produce an iron oxide silicate slag suitable for the formation of wrought iron in accordance with, the Aston process. If smaller capacity is desired one of the furnaces may be used alone. In any event,

whether one or both of the furnaces are used, quantities of molten slag are available at spaced intervals so as to coordinate with the other units of the plant, as will presently be described.

There are provided a plurality of shotting machines designated generally by reference numeral 2i and a press designated generally by reference numeral 22. The shotting machines 2| are mounted on a working floor or platform 23 which may conveniently be at the same level as the platform 9 and may form a continuation thereof. Trains of slag receptacle cars 24 are adapted to be moved to a position beneath the shotting machines and to another position adjacent the press on a track 25 by means of any suitable source of motive power. An electric loco-motive i5 may conveniently be used for this purpose. The track 25 is preferably disposed at the working level of the plant, taken as a whole, which is a substantial distance below the level of the working floor 23 and may conveniently be at the level of the track 21, presently to be described. The specific construction of the shotting machines forms no part of the present invention and therefore will not be described in detail. Such construction is described and claimed in said copending application Serial No. 537,856.

Any number of the shotting machines may be used, depending upon the capacity of operation desired. Previous to the shotting operation of any given shotting machine a slag receptacle carried on one of the slag receptacle cars 24 is placed directly beneath the shotting machine. Prior to being placed beneath the shotting machine, however, such slag receptacle is provided with a quantity of molten slag either from the slag furnaces or from excess slag from another slag receptacle, or both.

Considering, for example, initiation of operation of the plant, and assuming that only two of the shotting machines are to be operated, a quantity of suitable molten slag is first prepared in one of the slag furnaces, and such furnace is tapped either into a ladle (not shown) carried and manipulated by an overhead crane I6, which ladle in turn supplies the slag to two slag receptacles mounted on cars which, in initiation of operation of the plant, may, if desired, be positioned on the track adjacent the slag furnaces,

or into the two slag receptacles themselves, in which case the slag receptacles are lifted from the cars by the overhead crane and in turn held in position-to receive the slag tapped from the furnace. The two slag receptacles are preferably filled approximately half full of slag. The cars carrying such two slag receptacles are then moved along the track 25 until the receptacles lie directly beneath the two shotting machines which are to operate as above stated.

Meanwhile molten ferrous material has been prepared in one of the cupolas and has been transferred as above explained to one of the Bessemer converters where it is refined. After completion of the refining operation the converter discharges its contents into a transfer ladle removably mounted on a car movable longitudinally on a track 27 which extends to a position directly opposite the shotting machines. The car is then moved along the track 2'! to a position approximately opposite the two shotting machines which are to operate, at which point the transfer ladle is picked up by an overhead crane G3 and a portion of its contents is poured into the shutting ladle ofeach of the shutting machines which is to operate. The amount of ferrous material poured into each shutting machine is determined by the scale upon which the shutting machine is mounted. An operator on the platform watches the scale dial and signals: the crane operator when to stop pouring. If convenient the transfer ladle may be completely emptied into the two shutting machine ladles, although if it should be desired to introduce into the shutting machine ladles less than all of the material in the transfer ladle, such ladle containing the residue of the molten ferrous material is withdrawn and the molten ferrous material may be maintained in the transfer ladle until the succeeding shotting operation, when it may be poured into one or more of the shutting machine'ladles. This procedure is of advantage when, for example, it is desired to pour relatively small amounts of molten ferrous material into the shutting machine ladles for the purpose of forming relatively small balls of wrought iron. It would be undesirable to proportionately reduce the amount of material in a converter heat, and one converter heat may thus be used for more than one shutting operation. The molten ferrous material in the transfer ladle remains hot enough so that if there is no undue delay before the next shutting operation it may be made use of just as though it had originally been poured into the shutting machine ladles.

The pouring of the molten ferrous material from the shutting machine ladles into the slag receptacles is fully described and illustrated in said Wille patents, and as the specific manner of pouring forms no part of the present invention it will not be described here in detail.

After therequired amount of ferrous material has been introduced into each slag receptacle the cars 2 are removed from beneath the floor 23 to a convenient position for removal of excess slag. It is preferred to remove excess slag at a position adjacent the press 22, and. such position will for convenience be called the slag transfer station. It is found desirable to remove excess slag by decanting and tothis end it is convenient to lift the slag receptacle and tilt it. The overhead crane it may conveniently be used for this purpose. Excess slag will thereby be decanted from the receptacle, the ball remaining therein.

. The ball is removed from the slag receptacle to the press, this preferably being done by substantially inverting the slag receptacle and dumping out the ball. It is. preferred to dump the ball directly into the press and then to compress it toform a bloom of wrought ironwhich may then be given any desired treatment, such as rolling, to produce wrought iron articles.

As the wrought iron is adapted for fabrication into many different products of different sizes andshapes, and as unfinished shapes such as billets, slabs, etc., of different sizes are desirable for producing the various finished articles, it is likewise desirable to produce in the blooming mill billets and slabs of various difierent cross-sections and lengths. However, it is impracticable to attempt to form in a blooming mill widely different sizes and shapes of slabs and billets from blooms of standard size. Therefore provision is made for supplying blooms of various sizes, and as the size of a bloom depends upon the size of the wrought iron sponge or ball, balls of different sizes are made to conform with the productsto be rolled on the blooming mill.

While it is ordinarily desirable to empty a shutting machine ladle at each shutting operation, nevertheless if relatively smallballs are to be formed the shutting machine ladle may be only partly emptied during one shutting operation and may be completely emptied upon the succeeding operation, orthe residue remaining in it after the first shutting operation may be replenished by additional molten ferrous material and part or all of the aggregate thus formed may be poured into the slag bath upon the succeeding shutting operation. The provision of the scale makes possible close control of the size of the ball even though only part of the ferrous material is poured out of the shutting machine ladle into the slag bath at one shutting operation, and even though the ferrous material is replenished before the succeeding shutting operation.

It sometimes happens that a relatively small v quantity. of slabs or billets of a particular size a tions. A small ball and a relatively large ball, for

example, may be formed at the same time. The small ball produces a small bloom which,in turn, is suitable for rolling in the blooming mill into the desired number of slabs or billets of the desired size.

If the entire heat were utilized for the formation of balls of the same size this desirable result would not be possible. Likewise, the desirable result would not be possible if all of the balls made at one shutting operation should be of the same size.

The provision of the scale also makes possible regulation and control of therate of pour. As a shutting machine ladle is progressively emptied during shutting, the operator on the platform by watching the scale dial can observe the decrease in Weight of the shutting ladle and contents, which is equivalent to the weight of the ferrous material poured into the slag bath. By suitably controlling the tilting of the ladlea desired rate of pour can be obtained. The rate of pour is preferably maintained uniform, although if for any reason it should be desired to do so the rate could be altered during the pour. Certain methods of and apparatus for controlling the pour are described and claimed in the copending application of Edward B. Story and William T. Case, Serial No. 628,125, filed August 10, 1932,

It is preferred to have a second slag receptacle at the slag transfer station during decanting of each slag receptacle and to decant the excess slag directly into the second receptacle. The second receptacle is preferably at the working level, that is to say, the same level occupied by the first slag receptacle before it is lifted for decanting. This eliminates the provision of a plurality of working levels at the slag transfer station.

It is convenient to utilize a train comprising at least one more slag receptacle car than there are shutting machines. in operation. For example, with two shutting machines in operation it would be preferable to use a three-car train, two of the cars having slag receptacles provided with slag and the third car having an empty slag receptacle. After completion of the shot ting operation and removal of the train to the slag transfer station one of the filled receptacles would first decant its excess slag into the empty slag receptacle and then dump out its ball intothe press. Then the second filled slag receptacle would decant its excess slag into the slag receptacle just emptied and dump its ball into the press, the last slag receptacle emptied being used as the empty slag receptacle for the succeeding shotting operation. If desired, the last slag receptacle can be held at the slag transfer station until the return of the two cars having filled receptacles after the succeeding shotting operation, whereupon such empty receptacle can be placed on its car and the decanting procedure above described repeated. It is sometimes preferable, in order to equalize heat transfer, to use twice as many slag receptacle cars as there are shotting machines in operation so that each slag receptacle will be alternately filled and empty.

The excess slag is preferably reused while still molten for the formation of one or more additional balls. The slag receptacle containing the excess slag is returned to the shotting or pouring station where the shotting or pouring operation is repeated. ,By the use of the improved processes it is possible to speed up the operationsufliciently that the measures previously taken to conserve the heat of the slag can be eliminated. It has heretofore been proposed to conserve the heat of the slag by using a heat insulated slag receptacle, this having been found necessary or desirable when the operatipn was carried out so slowly that there was danger that the slag would be too'low in temperature for proper ball formation by the time the subsequent shotting operation could be carried out. The provision of insulated slag receptacles entailed additional expense and was also the cause of operating difficulties, and these advantages are eliminated by doing away with the insulation for the slag receptacles and returning the slag receptacle with the excess Slag to the pouring station so quickly that the slag remains at proper temperature. Uninsulated slag receptacles may therefore be used. Furthermore, uninsulated receptacles need not be handled so carefully as insulated receptacles and this aids in speeding up the operation.

By uninsulated slag receptacles I mean slag receptacles which do not have insulating material applied previously to their use and of a different character than material contained within the receptacles during use. The slag receptacles used in my process may acquire a skull or lining of solidified slag which may have insulating properties, but such skull or lining does not make my receptacles insulated receptacles within the meaning intended.

Additions may be made to the slag before reuse, and it is preferred to replenish the molten slag with additional molten slag from the slag furnaces, and preferably with molten slag having the same characteristics or whose analysis is approximately the same as that of the excess slag. The process as described in said Wille patents comprises incorporating ferrous material with molten slag in a receptacle at the processing station to form a ball, moving the receptacle to the slag transfer station, there transferring excess slag from such receptacle into another receptacle, moving the excess slag to a slag supply station, preferably adjacent the slag furnaces, there commingling at least a portion of the excess slag with additional molten slag, and subsequently incorporating ferrous material with thecommingled slag to form another ball. I find it of considerable advantage to effect the slag replenishment at the slag transfer station. To this end I tap one of the slag furnaces [3 into a receptacle carried by the overhead crane l6 and move such crane, carrying with it the slag-containing receptacle, to the slag transfer station. At such station the slag replenishment is effected. One of the slag receptacles may be carried by the crane to the slag furnaces to receive the slag tapped therefrom, or a ladle of ordinary construction may be used to convey the slag across the slag furnaces to the slag transfer station,

where the ladle may pour its contents or a por- 1 tion thereof into one of the slag receptacles to form a part or all of the slag for a succeeding shotting operation. The slag for initiation of the operation of the plant may likewise be introduced into the slag receptacles at the slag transi fer station if desired in preference to moving the train around to a position near the slag furnaces.

The efifecting of the slag replenishment at the slag transfer station has several advantages. It eliminates the movement of the train around to the position adjacent the slag furnaces each time replenishment is to be effected, and makes it possible for the train to simply shuttle back and forth between the shotting station and the slag transfer station. This saves valuable time as well as the power required to operate the train around the portion of the track leading to the position adjacent the slag furnaces. It may be desirable to utilize two overhead cranes, one to effect the slag transfer and the other to carry over from the slag furnaces the slag to be used for replenishing the excess or residual slag. If this is done the slag replenishment can be effected just as soon as the slag transfer operation has been completed.

- The slag temperature can be controlled by replenishment with molten slag from the slag furnace. During the shotting operation the ferrous material, being hotter than the slag, gives up heat to the slag and the slag therefore becomes appreciably hotter and may become undesirably hot, that is to say, so hot that the proper temperature differential would not be obtained if it should be attempted to again pour ferrous material into the excess slag. On account of the rapidity with which the operation may be carried out by using the improved processes the excess slag may not cool down to a temperature equivalent, say, to the temperature of the slag tapped from the slag furnace. Consequently the addition of a proper amount of slag from the slag furnace will bring down the temperature of the slag to such a point that the desired differential may be obtained. The temperature may be closely controlled by regulating the amount of slag added from the slag furnace.

Occasionally, due to unforeseen interruptions, a batch of excess slag may have to stand so long as to become undesirably cool. As above mentioned, the temperature of such slag was formerly attempted to be maintained by the use of heat insulating material in connection with the slag receptacle. However, the slag can be brought up to such a temperature that the proper differential may be obtained by adding a proper amount of slag from the slag furnace. When the excess slag has cooled down below the temperature of the slag in the slag furnace the greater the amount of slag added from the slag furnace the higher will be the temperature of the resultant mixture or aggregate. These features are described and claimed in said copending application of Aston and Story.

It is known to be desirable to form a ball having at least one horizontal dimension greater than its vertical dimension, and such a ball may conveniently be formed by utilizing my improved processes even though excess slag is returned without replenishment to the pouring station. The ferrous material may be distributed over the surface of the slag so as to produce a ball having at least one horizontal dimension greater than its vertical dimension regardless of the height of the slag in the slag receptacle during pouring. Therefore it is possible to reuse the same slag a number of times Without replenishment while still obtaining highly desirable results.

The movement of the shotting machines is, of course, stopped before the slag receptacles are moved from under the machines. The shotting ladles are restored to their respective vertical positions for receiving another charge of ferrous material from the transfer ladle and the entire cycle of operations may then be repeated.

I have thus provided methods for rapidly and efficiently carrying out the Aston process for the manufacture of wrought iron. The operations of the shotting machines are largely automatic and a minimum of manual control islnecessary. This makes it possible for a comparatively large installation to be controlled by few men With a resulting lowering in costs of production. The plant layout is such that the operation is of the line variety so that no unnecessary transporation of material in process is necessary.

The movement of the shotting machines is such as to secure a uniform distribution of the metal throughout the slag so that a superior quality of wrought iron is produced.

Although I have illustrated but a single preferred embodiment of my invention, I do not intend to be limited to the specific details thereof since the invention may be practiced in other forms. Minor changes and alterations will be apparent to those skilled in the art and all such changes may be made without departing from the invention as defined by the appended claims.

I claim:

1. A method of making wrought iron, comprising incorporating ferrous material with molten slag in a receptacle at a processing station to form a ball, moving the receptacle to a slag transfer station, there transferring excess slag therefrom into another receptacle, separately conveying additional molten slag from a slag supply station to the slag transfer station, commingling at least a portion of said additional molten slag and said excess slag at said slag transfer station, and subsequently incorporating ferrous material with said comminglecl slag to form another ball.

2. In the manufacture of wrought iron by the Aston process whichvnormally comprises incorporating ferrous material with molten slag in a receptacle at a processing station to form a ball, moving the receptacle to a slag transfer station, there transferring excess slag therefrom into another receptacle, moving said excess slag to a slag supply station, there commingling at least a portion of said excess slag with additional molten slag, and subsequently incorporating ferrous material with said commingled slag to form another ball, the step comprising separately conveying additional molten slag from the slag supply station to the slag transfer station and there commingling at least a portion of said additional molten slag with at least a portion of said excess slag, whereby to render unnecessary movement. of a receptacle containing excess slag from the slag transfer station to the slag supply station.

CHARLES EQGROSS. 

